首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3307篇
  免费   188篇
  国内免费   18篇
耳鼻咽喉   31篇
儿科学   94篇
妇产科学   122篇
基础医学   440篇
口腔科学   89篇
临床医学   293篇
内科学   609篇
皮肤病学   86篇
神经病学   263篇
特种医学   61篇
外科学   357篇
综合类   20篇
一般理论   3篇
预防医学   528篇
眼科学   96篇
药学   206篇
中国医学   22篇
肿瘤学   193篇
  2024年   3篇
  2023年   44篇
  2022年   105篇
  2021年   177篇
  2020年   99篇
  2019年   152篇
  2018年   168篇
  2017年   117篇
  2016年   109篇
  2015年   111篇
  2014年   172篇
  2013年   203篇
  2012年   279篇
  2011年   299篇
  2010年   169篇
  2009年   147篇
  2008年   214篇
  2007年   187篇
  2006年   160篇
  2005年   153篇
  2004年   132篇
  2003年   84篇
  2002年   83篇
  2001年   9篇
  2000年   8篇
  1999年   5篇
  1998年   14篇
  1997年   17篇
  1996年   8篇
  1995年   7篇
  1994年   10篇
  1993年   5篇
  1992年   4篇
  1989年   5篇
  1988年   2篇
  1987年   5篇
  1984年   6篇
  1983年   3篇
  1982年   3篇
  1981年   3篇
  1979年   5篇
  1976年   3篇
  1974年   3篇
  1965年   2篇
  1959年   1篇
  1954年   1篇
  1944年   1篇
  1943年   1篇
  1942年   1篇
  1934年   2篇
排序方式: 共有3513条查询结果,搜索用时 15 毫秒
61.
62.
63.

Introduction:

Causes of death are different and very important for policy makers in different regions. This study was designed to analyze the data for our in-patient children mortality.

Materials and Methods:

In this cross-sectional study from March 2011 to March 2013, all patients from 2 months to 18 years who died in pediatric intensive care unit, emergency room or medical pediatric wards in the teaching hospitals were studied.

Results:

From a total of 18,915 admissions during a 2-year-period, 256 deaths occurred with a mean age of 4.3 ± 5 years and mortality 1.35%. An underlying disease was present in 70.7% of the patients and in 88.5% of them the leading causes of death were related to the underlying diseases. The most common underlying diseases were congenital heart disease and cardiomyopathy in 50 (27.6%). The four main causes of deaths were sepsis (14.8%), pneumonia (14.5%), congestive heart failure (9.8%), and hepatic encephalopathy (9.8%).

Conclusion:

We may conclude that after sepsis and pneumonia, congestive heart failure, and hepatic encephalopathy are the leading causes of death. Most patients who died had underlying diseases including malignancies, heart and liver diseases as the most common causes.  相似文献   
64.
Colorectal cancer in patients under close colonoscopic surveillance   总被引:7,自引:0,他引:7  
BACKGROUND & AIMS: Colonoscopic polypectomy is considered effective for preventing colorectal cancer (CRC), but the incidence of cancer in patients under colonoscopic surveillance has rarely been investigated. We determined the incidence of CRC in patients under colonoscopic surveillance and examined the circumstances and risk factors for CRC and adenoma with high-grade dysplasia. METHODS: Patients were drawn from 3 adenoma chemoprevention trials. All underwent baseline colonoscopy with removal of at least one adenoma and were deemed free of remaining lesions. We identified patients subsequently diagnosed with invasive cancer or adenoma with high-grade dysplasia. The timing, location, and outcome of all cases of cancer and high-grade dysplasia identified are described and risks associated with their development explored. RESULTS: CRC was diagnosed in 19 of the 2915 patients over a mean follow-up of 3.7 years (incidence, 1.74 cancers/1000 person-years). The cancers were located in all regions of the colon; 10 were at or proximal to the hepatic flexure. Although most of the cancers (84%) were of early stage, 2 participants died of CRC. Seven patients were diagnosed with adenoma with high-grade dysplasia during follow-up. Older patients and those with a history of more adenomas were at higher risk of being diagnosed with invasive cancer or adenoma with high-grade dysplasia. CONCLUSIONS: CRC is diagnosed in a clinically important proportion of patients following complete colonoscopy and polypectomy. More precise and representative estimates of CRC incidence and death among patients undergoing surveillance examinations are needed.  相似文献   
65.
Objective: To determine the association between mode of delivery and maternal complications in patients with severe preeclampsia.

Methods: A prospective cohort study was conducted with 500 pregnant women with severe preeclampsia. The mode of delivery, vaginal or caesarean section, was considered the exposure, while the postpartum maternal complications and severe maternal morbidity were the outcomes. Logistic regression analysis was performed to determine the adjusted risk and 95% confidence intervals (95% CI) of maternal morbidity.

Results: Labour was spontaneous in 22.0% and induced in 28.2%, while 49.8% had an elective caesarean section. Ninety-five (67.4%) of the patients in whom labour was induced delivered vaginally. Total Caesarean rate was 68.2%. The risk of severe maternal morbidity was significantly greater in patients submitted to Caesarean section (54.0% versus 32.7%) irrespective of the presence of labour. Factors that remained associated with severe maternal morbidity following multivariate analysis were a diagnosis of HELLP syndrome after delivery (OR?=?3.73; 95% CI: 1.55–9.88) and having a caesarean (OR?=?1.91; 95% CI: 1.52–4.57).

Conclusions: Caesareans are often performed in patients with severe preeclampsia and are associated with significant postpartum maternal morbidity. Induction of labour should be considered a feasible option in these patients.  相似文献   

66.
Limb/digit amputation is a common event in humans caused by trauma, medical illness, or surgery. Although the loss of a digit is not lethal, it affects quality of life and imposes high costs on amputees. In recent years, the increasing interest in limb regeneration has led to enhanced scientific knowledge. However, the limited ability to develop functional limb regeneration in the clinical setting suggests that a challenging issue remains in limb regeneration. Recently, the emergence of regenerative engineering is a promising field to address this challenge and close the gap between science and clinical applications. Cell signalling and molecular mechanisms involved in the limb regeneration process have been extensively studied; however, there is still insufficient data on cell therapy and tissue engineering for limb regeneration. In this review, we intend to focus on therapeutic approaches for limb regeneration that are closely related to gene, immune, and stem cell therapies, as well as tissue engineering approaches that take into consideration the peculiar developmental properties of the limbs. In addition, we attempt to identify the challenges of these strategies for limb regeneration studies in terms of clinical settings and as a road map to accomplish the goal of functional human limb regeneration.  相似文献   
67.
Problem: Studies on leadership identity development through reflection with Team-Based Learning (TBL) in medical student education are rare. We assumed that reflection and feedback on the team leadership process would advance the progression through leadership identity development stages in medical students within the context of classes using TBL. Intervention: This study is a quasi-experimental design with pretest–posttest control group. The pretest and posttest were reflection papers of medical students about their experience of leadership during their TBL sessions. In the intervention group, TBL and a team-based, guided reflection and feedback on the team leadership process were performed at the end of all TBL sessions. In the other group, only TBL was used. The Stata 12 software was used. Leadership Identity was treated both as a categorical and quantitative variable to control for differences in baseline and gender variables. Chi-square, t tests, and linear regression analysis were performed. Context: The population was a cohort of 2015–2016 medical students in a TBL setting at Tehran University of Medical Sciences, School of Medicine. Teams of four to seven students were formed by random sorting at the beginning of the academic year (intervention group n = 20 teams, control group n = 19 teams). Outcome: At baseline, most students in both groups were categorized in the Awareness and Exploration stage of leadership identity: 51 (52%) in the intervention group and 59 (55%) in the control group: uncorrected χ2(3) = 15.6, design-based F(2.83, 108) = 4.87, p = .003. In the posttest intervention group, 36 (36%) were in exploration, 33 (33%) were in L-identified, 20 (20%) were in Leadership Differentiated, and 10 (10%) were in the Generativity. None were in the Awareness or Integration stages. In the control group, 3 (20%) were in Awareness, 56 (53%) were in Exploration, 35 (33%) were in Leader Identified, 13 (12%) were in Leadership Differentiated. None were in the Generativity and Integration stages. Our hypothesis was supported by the data: uncorrected χ2(4) = 18.6, design-based F(3.77, 143) = 4.46, p = .002. The mean of the leadership identity in the pretest, intervention group equaled 1.93 (SD = 0.85) and the pretest, control group mean was 2.36 (SD = 0.86), p = .004. The mean of the posttest, intervention group was 3.04 (SD = 0.98) and posttest, control group mean was 2.54 (SD = 0.74), T = ?4.00, design df = 38, p < .001, and adjusted on baseline and gender T = ?8.97, design df = 38, p < .001. Lessons Learned: Reflection and feedback on the team leadership process in TBL advances the progression in stages of leadership identity development in medical students. Although the TBL strategy itself could have an impact on leadership identity development, this study demonstrates that when a reflection and feedback on leadership intervention are added, there is much greater impact.  相似文献   
68.

Background

As one of the most common work-related musculoskeletal disorders and postural deviations, forward head posture (FHP), is considered to lead to muscle imbalance.

Objectives

The aim of this study is to investigate the bilateral cross-sectional area (CSA) of the deep neck flexor muscles at rest and during five stages of the craniocervical flexion (CCF) test in individuals with FHP and the controls with normal head posture.

Methods

Eighteen students with FHP and 18 controls with normal head posture, all females aged 18–35 years, participated in this study. Participants were categorized into two groups based on their craniovertebral angle. The CSA of the deep neck flexors was measured using ultrasonography while participants lay supine on the table with a pressure biofeedback unit placed under their necks in order to let the examiner measure the CSA of the muscles during rest and five stages of the CCF test including 22, 24, 26, 28, and 30 mmHg of the pressure biofeedback unit.

Results

A significant effect of contraction level was observed in both groups, indicating significant increases of the CSA of the deep neck flexors during contraction (F = 64.37, P < 0.001). No significant difference was evident for the CSA of the deep neck flexors between the groups, although the increase in the CSA of the deep neck flexors was up to 28 mmHg in the normal head posture group compared to 26 mmHg in the FHP group.

Conclusions

The results of the present study showed no significant difference between the performance of the deep neck flexors during the CCF test in FHP and normal head posture individuals, which challenge the common belief of the deep neck flexors weakness in individuals sustaining FHP.  相似文献   
69.

OBJECTIVE:

to evaluate the indexes and the main factors associated with non-adherence to medication treatment for systemic arterial hypertension between urban and rural areas.

METHOD:

analytical study based on an epidemiological survey with a sample of 247 hypertensive residents of rural and urban areas, with application of a socio-demographic and economic questionnaire, and treatment adherence assessment. The Pearson''s Chi-square test was used and the odds ratio (OD) was calculated to analyze the factors related to non-adherence.

RESULTS:

the prevalence of non-adherence was 61.9% and it was higher in urban areas (63.4%). Factors significantly associated with non-adherence were: male gender (OR=1.95; 95% CI 1.08-3.50), age 20-59 years old (OR=2.51; 95% CI 1.44-4.39), low economic status (OR=1.95; 95% CI 1.09-3.47), alcohol consumption (OR=5.92, 95% CI 1.73-20.21), short time of hypertension diagnosis (OR=3.07; 95% CI 1.35-6.96) and not attending the health service for routine consultations (OR=2.45; 1.35-4.42).

CONCLUSION:

the socio-demographic/economic characteristics, lifestyle habits and how to relate to health services were the factors that presented association with non-adherence regardless of the place of residence.  相似文献   
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号